In surface coating processes, the density, efficiency and/or uniformity of the coating(s) are parameters that typically affect performance of products such as stents, hemostatic sponges or other medical devices. Typically, biologics or drugs are incorporated in such coatings, and measuring the density, uniformity, or coating efficiency associated with these compounds is often difficult or impossible without destruction of at least a portion of the coating.
Further, manufacturing processes often involve exposure of articles to critical environmental conditions, such as temperature, humidity, or electromagnetic radiation. It is not always easy to assure that every article from a manufacturing line has been properly exposed to critical environmental conditions, or that every article has not been exposed to unacceptable environmental conditions. Sometimes, only portions of the article are inadequately or unacceptably exposed. Similarly, handling of products after release often requires that they are not exposed to unacceptable environmental conditions.
Additionally, manufacturing processes often involve quality control processes to assure that product contents match the product's label. Failure of such control processes may result in occurrence of packaging mismatch, with potential adverse consequences to the product's end user.
Products that can benefit from quality control of the density, efficiency and/or uniformity of the coating include single-use surgical devices, implantables, sutures, products sterilized according to custom procedure by customers after purchase, hysteroscope, drug coated contact lenses, reagent coatings for diagnostic products, and enteric coatings on pharmaceuticals.
Products that can benefit from monitoring required environmental exposure or exposure to unacceptable environmental conditions include products stored and distributed in cold-chain systems, sunscreens, and consumer products with finite shelf life.
Products that can benefit quality control processes to assure that product contents match the product's label include consumer products, pharmaceutical products, medical diagnostics, and medical devices.
Further, counterfeiting of manufactured goods, including those that incorporate coated surfaces is a global issue. It is estimated that 5% of all world trade in branded goods is counterfeit (ten Ham, Drug Saf., 2003, 26: 991-7). A counterfeit product often appears confusingly similar to that of a genuine product. The material of a counterfeit product may be the same as, or different from the material of a genuine product. Often the counterfeiting product has inferior quality as compared to that of a genuine product. There is a continuing need to develop novel methods to combat counterfeiting at the manufacturing stage and for detection counterfeit goods in the distribution chain.
Methods have been developed to identify genuine products and distinguish them from counterfeit products. For example, various analytical methods have been used to detect components in pharmaceutical products, with emphasis on the identification of differences among manufacturers that can be used for source verification in suspect/counterfeit cases. Such methods include, but are not limited to, capillary electrophoresis (Flurer et al, Journal of Chromatography, A, 1994, 674: 153-63), thin-layer chromatography (Pachaly et al., Pharmazeutische Industrie, 1993, 55: 259-67), near-infrared spectroscopy (Scafi et al, Analyst. 2001, 126: 2218-24; and Olsen et al., Pharmaceutical Technology North America, 2002, 26: 62-71), and calorimetric assay (Green et al, Tropical Medicine & International Health, 2001, 6: 980-982).
Other methods have been developed to establish identity and source of the product, sometimes including a pharmaceutical product, by marking the product. For example, bar code symbols placed on the outside of the medication may be used for prescription medication identification (U.S. Pat. No. 5,845,264); a mixture of at least two photochromic compounds that have different absorption maxima in the activated state may be incorporated into a carrier composition, e.g., ink, paint, fiber or polymer to form the authenticating display data on the article (U.S. Pat. No. 5,289,547); a solution of a target nucleic acid may be incorporated in an object for security crypto-marking of the object (U.S. Pat. No. 5,139,812); a hapten may be associated with the product as a marker (U.S. Pat. No. 5,429,952); compositions that are uniquely luminescent may be incorporated or applied to materials for verifying products or documents (U.S. Pat. No. 6,402,986); and constituents intrinsically located or extrinsically placed in an object (such as a pharmaceutical) may be detected by x-ray fluorescence analysis to identify or verify the object or its point of manufacture (US 20040022355). In addition, U.S. Pat. No. 5,599,578 describes a method for labeling an object for its verification by applying a mark to said object with a visible ink that contains a component that is invisible to the naked eye, such as a dye that is visible only in the presence of selected radiation, or an ink that displays a selected measurable electrical resistivity, or an ink containing a biologic marker. WO 2004041328 describes methods for marking a pharmaceutical product, container or pharmaceutical packaging system with a scent to establish the identity and/or source of the pharmaceutical.
The substance(s) used to mark a product can be visible, such as a dye or colored molecule. They can also be invisible to the unaided eyes, thus are a “covert” marker of a substance. Covert markers are typically more difficult to replicate, simulate, alter, transpose, and are less subject to tampering. WO 2005111127 describes a method for incorporating covert markers into an article in the form of metals and their salts and oxides into plastics, then detecting net changes in magnetic field around said article.
Microparticles have been used to mark a product for authentication. In some embodiments, microparticles have been used as the “cargo” to host the coding elements like molecules or nanoparticles with identifiable features (Finkel et al., Oct. 1, 2004, Analytical Chemistry, 352A-359A, and references therein). U.S. Pat. No. 4,053,433 describes a method of marking a substance with microparticles that are encoded with an orderly sequence of visually distinguishable colored segments that can be decoded with a microscope or other magnifying device. Additionally, microparticles have been used as part of the coding element, where the physical properties of the microparticles are used as the coding elements, and most code deciphering is accomplished by recognizing a physical pattern formed by the compilation of various microparticles (Finkel et al., 2004 supra and references therein). U.S. Pat. No. 4,767,205 discloses an identification method involving an identification code that is based upon a selected number of groups of microparticles, wherein each group is made of highly uniform microparticles of substantially the same uniform size, shape and color with the specific combination of size, shape and color in one group not being repeated in any other group. U.S. Pat. No. 6,647,649 discloses a process for marking an article by applying thereto a tag, which comprises a plurality of microparticles having two or more distinguishable marker layers corresponding to a predetermined numeric code.
Despite these efforts, drug and medical devices counterfeiting remains a worldwide problem. There is a continuing need to develop novel methods to combat counterfeit drugs and devices at the manufacturing stage and for detection in the distribution chain. One effective way to fight counterfeiting is to mark a product with an authentication or product identification code that is not easily imitated or counterfeited. The present invention provides a methodology for quality control of surface coatings that is also readily adaptable to product authentication by incorporating a unique product signature for authenticating, tracking or tracing articles manufactured according to the quality control procedures of the invention. The invention further relates to providing a means to detect proper and/or improper handling or storage of articles manufactured according to the quality control procedure of the invention.
The present invention also relates to a method for assuring that product contents' match product's label using microparticulate taggants having different detectable physical properties, wherein each combination of properties is used as an encoding bit to create codes. The present invention thus further extends the utility of using the count or relative count of microparticles or symbols to create an authentication code in order to minimize the occurrence of packaging mismatch errors by providing a coding system that can be incorporated into product contents, into or onto product packaging containers, and into or onto product labels. The coding system provides for multiple checkpoints to assure against mix-up errors.